phase 2

docs/point_table_design.md

@@ -0,0 +1,20 @@
+# 点表设计
+
+配置文件：`config/point_table.json`（YAML 镜像：`config/point_table.yaml`）
+
+## 映射关系
+
+```
+ValveOpening
+  ↔ AO_Channel_01        (physicalChannel)
+  ↔ ns=1;s=.../ValveOpening (opcuaNodeId)
+  ↔ control/cmd/EdgeDevice_01/ValveOpening/set (cmdTopic)
+  ↔ control/ack/EdgeDevice_01/ValveOpening (ackTopic)
+  ↔ data/EdgeDevice_01/ValveOpening (dataTopic)
+```
+
+由 `softbus_registry::PointRegistry` 加载并建立三向索引：`objectRef` / `topic` / `opcuaNodeId`。
+
+## 主题规则
+
+`config/topic_rule.json` 定义默认主题模板，点表可覆盖单点 `cmdTopic`/`dataTopic`。